Isoform-Specific Na,K-ATPase Alterations Precede Disuse-Induced Atrophy of Rat Soleus Muscle

Figure 2

Hindlimb suspension decreases excitability and alters electrogenesis of rat soleus muscle. (a) force-voltage relationships of twitch tensions in control soleus muscles (open circles, ), after 24 h (closed circles, ) and 72 h (triangles, ) of HS. Force-voltage relationships were determined using 1 ms stimuli (direct stimulation) of increasing voltage to elicit maximum force of twitch tension. % to force obtained at supramaximal stimulation is shown. Insert-expanded curve for voltages below 10 mV; points that significantly differ from corresponding control points are marked by asterix. (b) The resting membrane potential (white columns) and total electrogenic activity of the Na,K-ATPase (black columns) in control soleus muscles and after 24 h and 72 h of HS. ; compared to respective control.

(a)

(b)